A contact device of this kind is known, for example, from U.S. Pat. No. 4,222,019 which relates to a circuit breaker, in which the contact lever is disposed in the described manner, in the vicinity of the base of the switch housing and parallel to the switch. The end of the contact lever is pivotably supported on a displaceable bearing pin, which also includes a catch, acting as part of the switching lock of the switch. In the known switch, the stop is embodied in the free end of a transverse portion of the switch housing wall. A compression spring, supported on the housing base, acts upon the contact at a point which is located between the bearing pin and the stop. On the one hand, the compression spring generates the requisite contact pressure; on the other, this spring generates a force, which displaces the bearing pin transversely to the longitudinal direction of the contact lever, if the catch is tripped either by an excessive current or as the result of manual actuation of a tilt lever. Thus, under the force of the compression spring, the contact lever comes to rest at the stop and pivots about this stop, causing the separation of the contact lever from the fixed contact element.
In a contact device of this kind, the object is to exert great break-open force on the contact lever in order to assure the reliable breaking of the contact between the contact lever and the fixed contact element, although this contact is at most lightly welded. It is possible, per se, to attain a great break-open force by dimensioning the compression spring to act upon the contact lever in sufficiently massive fashion. However, since this compression spring also acts upon the catch and other tripping elements of the switching lock, an increase in the break-open force of the contact, brought about by making the compression spring more massive, produces an exactly proportional increase in the stress placed on the switching lock of the switch. This occasions increased mechanical wear of the tripping devices, which must accordingly be designed for greater tripping forces, although this is disadvantageous.